Sudden cardiac arrest (colloquially “heart attack”) is a regular killer. The best treatment for cardiac arrest is quick and competent chest compressions to keep blood flowing through a subject's heart. Generally, every minute of delay in treating a cardiac arrest subject lowers the chance of survival by about ten percent. As a result, the ability to provide CPR in a competent manner can be a very important personal skill, and is particularly important for professional healthcare workers such as emergency medical technicians (EMTs).
Various CPR feedback devices are available that indicate to a rescuer whether they are performing CPR chest compressions at an appropriate rate and an appropriate depth of compression, such as dictated by American Heart Association (AHA) guidelines.